Radiation detector with an intermediate layer

ABSTRACT

A radiation detector includes an intermediate layer, which is arranged between a detection layer with a number of detection elements and a number of readout units. In an example embodiment of this arrangement, the intermediate layer has a plurality of electrically-conductive connections between the detection elements and the readout units. An example embodiment further specifies a medical imaging system, as well as a method of using the heating apparatus.

PRIORITY STATEMENT

This application is a continuation of and claims priority under 35U.S.C. §§ 120/121 to U.S. patent application Ser. No. 15/798,626 filedOct. 31, 2017, which claims priority under 35 U.S.C. § 119 to Germanpatent application number DE 102016221481.0 filed Nov. 2, 2016, theentire contents of each of which are hereby incorporated herein byreference.

FIELD

At least one embodiment of the invention generally relates to aradiation detector, to a medical imaging system and/or to the use of aheating apparatus for heating a radiation detector.

BACKGROUND

In the development of radiation detectors—for example X-ray detectorsfor CT systems—an important consideration is to reduce manufacturingcosts ever further. The main costs of a CT detector in such cases may befound in the sensor board. This usually contains the direct-convertingor indirect-converting sensor material, the evaluation electronics (ASICand in a few assemblies the photodiode as well) and a carrier materialor carrier substrate, which may be needed as the base unit for thestructure as a whole and gives the sensor board its mechanicalstability.

The surface of ASIC in this case is usually equal to the surface of theoverall CT detector. This is the case for example in the technology forintegrating detectors, in which the photodiodes and the ASIC form oneunit. The advantage of this approach lies in the fact that the linelengths between photodiode and evaluation electronics are kept as ashort as possible in order to reduce electronic noise. Furthermore thetechnology has been developed to make smaller pixels in the detectorpossible.

With counting technology too the surface of the ASIC is usually equal tothe surface of the overall CT detector. A large unknown in thedevelopment of the counting technology is in certain parts the influenceof the input capacitance of a pixel on the response behavior and in suchcases in particular the linearity and noise behavior in combination withthe energy resolution of the ASIC. In order to take complexity and riskout of the development, the general aim has been to keep the inputcapacitances as low as possible and to keep them the same size. This maylead to a basic structure (see FIG. 1), in which the respective inputchannel of the ASIC is located directly on the sensor-side pad. The linelengths are minimized in such cases and where possible are designed sothat the input capacitances are the same for all pixels.

The disadvantage of this highly-integrated approach on the other hand isthe price. The ASIC costs are determined as a rule not by the functionscontained, but by the surface. In particular with a view to larger salesmarkets, the aim should thus be to reduce the costs.

SUMMARY

At least one embodiment of the present invention specifies a lower-costlayout for a radiation detector.

At least one embodiment of the invention is directed to a radiationdetector; at least one embodiment of the invention is directed to amedical imaging system; and at least one embodiment of the invention isdirected to a use of a heating apparatus for heating a radiationdetector.

The radiation detector of at least one embodiment comprises anintermediate layer, which is arranged between a detection layer with anumber of detection elements and a number of readout units. In this casethe intermediate layer has a plurality of electrically-conductiveconnections between the detection elements and the readout units.

The medical imaging system (e.g. CT), in at least one embodiment,comprises at least one embodiment of the radiation detector, preferablya direct-converting X-ray detector. The comparatively large surface ofthe detector in computed tomography results here for an inventiveradiation detector in an especially large potential for savings in themanufacturing costs. In addition the effect of the heating apparatuscomes into play especially effectively at the high radiation fluxdensities in CT devices and the high power losses associated therewith.

At least one embodiment of the invention is directed to a method to heata radiation detector, the method comprising:

controlling a heating apparatus, including a heating element, arrangedbetween a detection layer including a plurality of detection elementsand a plurality of readout units, to regulate a heating power,introduceable into the radiation detector to heat the radiationdetector.

At least one embodiment of the invention is directed to a method,comprising:

using a heating apparatus to heat a radiation detector, the heatingapparatus including

-   -   a heating element, arranged between a detection layer including        a plurality of detection elements and a plurality of readout        units, and    -   a control device, to control the heating apparatus and to        regulate a heating power, introduceable into the radiation        detector to heat the radiation detector.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in detail once again below withreference to the enclosed figures on the basis of example embodiments.In this description, in the various figures, the same components arelabeled with identical reference numbers. The figures are as a rule nottrue-to-scale. In the figures:

FIG. 1 shows a schematic sectional diagram of a prior-art radiationdetector,

FIG. 2 shows a schematic sectional diagram of an example embodiment ofan inventive radiation detector,

FIG. 3 shows a schematic sectional diagram of a further exampleembodiment of an inventive radiation detector,

FIG. 4 shows a schematic sectional diagram of a further exampleembodiment of an inventive radiation detector with heating apparatus,

FIG. 5 shows a diagram of a graph for explaining the regulation of theheating apparatus and

FIG. 6 shows a rough schematic diagram of an example embodiment of aninventive computed tomography system.

It should be pointed out in this context that the terms “top” and“bottom” here relate to the schematic diagram. In a radiation detectorinstalled in accordance with specifications “top” corresponds topointing in the direction of an (X-ray) radiation source and “bottom”accordingly pointing away from this direction (i.e. “top” corresponds tothe direction from which the radiation to be detected strikes thedetection elements).

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

The drawings are to be regarded as being schematic representations andelements illustrated in the drawings are not necessarily shown to scale.Rather, the various elements are represented such that their functionand general purpose become apparent to a person skilled in the art. Anyconnection or coupling between functional blocks, devices, components,or other physical or functional units shown in the drawings or describedherein may also be implemented by an indirect connection or coupling. Acoupling between components may also be established over a wirelessconnection. Functional blocks may be implemented in hardware, firmware,software, or a combination thereof.

Various example embodiments will now be described more fully withreference to the accompanying drawings in which only some exampleembodiments are shown. Specific structural and functional detailsdisclosed herein are merely representative for purposes of describingexample embodiments. Example embodiments, however, may be embodied invarious different forms, and should not be construed as being limited toonly the illustrated embodiments. Rather, the illustrated embodimentsare provided as examples so that this disclosure will be thorough andcomplete, and will fully convey the concepts of this disclosure to thoseskilled in the art. Accordingly, known processes, elements, andtechniques, may not be described with respect to some exampleembodiments. Unless otherwise noted, like reference characters denotelike elements throughout the attached drawings and written description,and thus descriptions will not be repeated. The present invention,however, may be embodied in many alternate forms and should not beconstrued as limited to only the example embodiments set forth herein.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions,layers, and/or sections, these elements, components, regions, layers,and/or sections, should not be limited by these terms. These terms areonly used to distinguish one element from another. For example, a firstelement could be termed a second element, and, similarly, a secondelement could be termed a first element, without departing from thescope of example embodiments of the present invention. As used herein,the term “and/or,” includes any and all combinations of one or more ofthe associated listed items. The phrase “at least one of” has the samemeaning as “and/or”.

Spatially relative terms, such as “beneath,” “below,” “lower,” “under,”“above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation in addition tothe orientation depicted in the figures. For example, if the device inthe figures is turned over, elements described as “below,” “beneath,” or“under,” other elements or features would then be oriented “above” theother elements or features. Thus, the example terms “below” and “under”may encompass both an orientation of above and below. The device may beotherwise oriented (rotated 90 degrees or at other orientations) and thespatially relative descriptors used herein interpreted accordingly. Inaddition, when an element is referred to as being “between” twoelements, the element may be the only element between the two elements,or one or more other intervening elements may be present.

Spatial and functional relationships between elements (for example,between modules) are described using various terms, including“connected,” “engaged,” “interfaced,” and “coupled.” Unless explicitlydescribed as being “direct,” when a relationship between first andsecond elements is described in the above disclosure, that relationshipencompasses a direct relationship where no other intervening elementsare present between the first and second elements, and also an indirectrelationship where one or more intervening elements are present (eitherspatially or functionally) between the first and second elements. Incontrast, when an element is referred to as being “directly” connected,engaged, interfaced, or coupled to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between,” versus “directly between,” “adjacent,” versus“directly adjacent,” etc.).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments of the invention. As used herein, the singular forms “a,”“an,” and “the,” are intended to include the plural forms as well,unless the context clearly indicates otherwise. As used herein, theterms “and/or” and “at least one of” include any and all combinations ofone or more of the associated listed items. It will be furtherunderstood that the terms “comprises,” “comprising,” “includes,” and/or“including,” when used herein, specify the presence of stated features,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items. Expressionssuch as “at least one of,” when preceding a list of elements, modify theentire list of elements and do not modify the individual elements of thelist. Also, the term “exemplary” is intended to refer to an example orillustration.

When an element is referred to as being “on,” “connected to,” “coupledto,” or “adjacent to,” another element, the element may be directly on,connected to, coupled to, or adjacent to, the other element, or one ormore other intervening elements may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to,”“directly coupled to,” or “immediately adjacent to,” another elementthere are no intervening elements present.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments belong. Itwill be further understood that terms, e.g., those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Before discussing example embodiments in more detail, it is noted thatsome example embodiments may be described with reference to acts andsymbolic representations of operations (e.g., in the form of flowcharts, flow diagrams, data flow diagrams, structure diagrams, blockdiagrams, etc.) that may be implemented in conjunction with units and/ordevices discussed in more detail below. Although discussed in aparticularly manner, a function or operation specified in a specificblock may be performed differently from the flow specified in aflowchart, flow diagram, etc. For example, functions or operationsillustrated as being performed serially in two consecutive blocks mayactually be performed simultaneously, or in some cases be performed inreverse order. Although the flowcharts describe the operations assequential processes, many of the operations may be performed inparallel, concurrently or simultaneously. In addition, the order ofoperations may be re-arranged. The processes may be terminated whentheir operations are completed, but may also have additional steps notincluded in the figure. The processes may correspond to methods,functions, procedures, subroutines, subprograms, etc.

Specific structural and functional details disclosed herein are merelyrepresentative for purposes of describing example embodiments of thepresent invention. This invention may, however, be embodied in manyalternate forms and should not be construed as limited to only theembodiments set forth herein.

Units and/or devices according to one or more example embodiments may beimplemented using hardware, software, and/or a combination thereof. Forexample, hardware devices may be implemented using processing circuitrysuch as, but not limited to, a processor, Central Processing Unit (CPU),a controller, an arithmetic logic unit (ALU), a digital signalprocessor, a microcomputer, a field programmable gate array (FPGA), aSystem-on-Chip (SoC), a programmable logic unit, a microprocessor, orany other device capable of responding to and executing instructions ina defined manner. Portions of the example embodiments and correspondingdetailed description may be presented in terms of software, oralgorithms and symbolic representations of operation on data bits withina computer memory. These descriptions and representations are the onesby which those of ordinary skill in the art effectively convey thesubstance of their work to others of ordinary skill in the art. Analgorithm, as the term is used here, and as it is used generally, isconceived to be a self-consistent sequence of steps leading to a desiredresult. The steps are those requiring physical manipulations of physicalquantities. Usually, though not necessarily, these quantities take theform of optical, electrical, or magnetic signals capable of beingstored, transferred, combined, compared, and otherwise manipulated. Ithas proven convenient at times, principally for reasons of common usage,to refer to these signals as bits, values, elements, symbols,characters, terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise, or as is apparent from the discussion,terms such as “processing” or “computing” or “calculating” or“determining” of “displaying” or the like, refer to the action andprocesses of a computer system, or similar electronic computingdevice/hardware, that manipulates and transforms data represented asphysical, electronic quantities within the computer system's registersand memories into other data similarly represented as physicalquantities within the computer system memories or registers or othersuch information storage, transmission or display devices.

In this application, including the definitions below, the term ‘module’or the term ‘controller’ may be replaced with the term ‘circuit.’ Theterm ‘module’ may refer to, be part of, or include processor hardware(shared, dedicated, or group) that executes code and memory hardware(shared, dedicated, or group) that stores code executed by the processorhardware.

The module may include one or more interface circuits. In some examples,the interface circuits may include wired or wireless interfaces that areconnected to a local area network (LAN), the Internet, a wide areanetwork (WAN), or combinations thereof. The functionality of any givenmodule of the present disclosure may be distributed among multiplemodules that are connected via interface circuits. For example, multiplemodules may allow load balancing. In a further example, a server (alsoknown as remote, or cloud) module may accomplish some functionality onbehalf of a client module.

Software may include a computer program, program code, instructions, orsome combination thereof, for independently or collectively instructingor configuring a hardware device to operate as desired. The computerprogram and/or program code may include program or computer-readableinstructions, software components, software modules, data files, datastructures, and/or the like, capable of being implemented by one or morehardware devices, such as one or more of the hardware devices mentionedabove. Examples of program code include both machine code produced by acompiler and higher level program code that is executed using aninterpreter.

For example, when a hardware device is a computer processing device(e.g., a processor, Central Processing Unit (CPU), a controller, anarithmetic logic unit (ALU), a digital signal processor, amicrocomputer, a microprocessor, etc.), the computer processing devicemay be configured to carry out program code by performing arithmetical,logical, and input/output operations, according to the program code.Once the program code is loaded into a computer processing device, thecomputer processing device may be programmed to perform the programcode, thereby transforming the computer processing device into a specialpurpose computer processing device. In a more specific example, when theprogram code is loaded into a processor, the processor becomesprogrammed to perform the program code and operations correspondingthereto, thereby transforming the processor into a special purposeprocessor.

Software and/or data may be embodied permanently or temporarily in anytype of machine, component, physical or virtual equipment, or computerstorage medium or device, capable of providing instructions or data to,or being interpreted by, a hardware device. The software also may bedistributed over network coupled computer systems so that the softwareis stored and executed in a distributed fashion. In particular, forexample, software and data may be stored by one or more computerreadable recording mediums, including the tangible or non-transitorycomputer-readable storage media discussed herein.

Even further, any of the disclosed methods may be embodied in the formof a program or software. The program or software may be stored on anon-transitory computer readable medium and is adapted to perform anyone of the aforementioned methods when run on a computer device (adevice including a processor). Thus, the non-transitory, tangiblecomputer readable medium, is adapted to store information and is adaptedto interact with a data processing facility or computer device toexecute the program of any of the above mentioned embodiments and/or toperform the method of any of the above mentioned embodiments.

Example embodiments may be described with reference to acts and symbolicrepresentations of operations (e.g., in the form of flow charts, flowdiagrams, data flow diagrams, structure diagrams, block diagrams, etc.)that may be implemented in conjunction with units and/or devicesdiscussed in more detail below. Although discussed in a particularlymanner, a function or operation specified in a specific block may beperformed differently from the flow specified in a flowchart, flowdiagram, etc. For example, functions or operations illustrated as beingperformed serially in two consecutive blocks may actually be performedsimultaneously, or in some cases be performed in reverse order.

According to one or more example embodiments, computer processingdevices may be described as including various functional units thatperform various operations and/or functions to increase the clarity ofthe description. However, computer processing devices are not intendedto be limited to these functional units. For example, in one or moreexample embodiments, the various operations and/or functions of thefunctional units may be performed by other ones of the functional units.Further, the computer processing devices may perform the operationsand/or functions of the various functional units without sub-dividingthe operations and/or functions of the computer processing units intothese various functional units.

Units and/or devices according to one or more example embodiments mayalso include one or more storage devices. The one or more storagedevices may be tangible or non-transitory computer-readable storagemedia, such as random access memory (RAM), read only memory (ROM), apermanent mass storage device (such as a disk drive), solid state (e.g.,NAND flash) device, and/or any other like data storage mechanism capableof storing and recording data. The one or more storage devices may beconfigured to store computer programs, program code, instructions, orsome combination thereof, for one or more operating systems and/or forimplementing the example embodiments described herein. The computerprograms, program code, instructions, or some combination thereof, mayalso be loaded from a separate computer readable storage medium into theone or more storage devices and/or one or more computer processingdevices using a drive mechanism. Such separate computer readable storagemedium may include a Universal Serial Bus (USB) flash drive, a memorystick, a Blu-ray/DVD/CD-ROM drive, a memory card, and/or other likecomputer readable storage media. The computer programs, program code,instructions, or some combination thereof, may be loaded into the one ormore storage devices and/or the one or more computer processing devicesfrom a remote data storage device via a network interface, rather thanvia a local computer readable storage medium. Additionally, the computerprograms, program code, instructions, or some combination thereof, maybe loaded into the one or more storage devices and/or the one or moreprocessors from a remote computing system that is configured to transferand/or distribute the computer programs, program code, instructions, orsome combination thereof, over a network. The remote computing systemmay transfer and/or distribute the computer programs, program code,instructions, or some combination thereof, via a wired interface, an airinterface, and/or any other like medium.

The one or more hardware devices, the one or more storage devices,and/or the computer programs, program code, instructions, or somecombination thereof, may be specially designed and constructed for thepurposes of the example embodiments, or they may be known devices thatare altered and/or modified for the purposes of example embodiments.

A hardware device, such as a computer processing device, may run anoperating system (OS) and one or more software applications that run onthe OS. The computer processing device also may access, store,manipulate, process, and create data in response to execution of thesoftware. For simplicity, one or more example embodiments may beexemplified as a computer processing device or processor; however, oneskilled in the art will appreciate that a hardware device may includemultiple processing elements or processors and multiple types ofprocessing elements or processors. For example, a hardware device mayinclude multiple processors or a processor and a controller. Inaddition, other processing configurations are possible, such as parallelprocessors.

The computer programs include processor-executable instructions that arestored on at least one non-transitory computer-readable medium (memory).The computer programs may also include or rely on stored data. Thecomputer programs may encompass a basic input/output system (BIOS) thatinteracts with hardware of the special purpose computer, device driversthat interact with particular devices of the special purpose computer,one or more operating systems, user applications, background services,background applications, etc. As such, the one or more processors may beconfigured to execute the processor executable instructions.

The computer programs may include: (i) descriptive text to be parsed,such as HTML (hypertext markup language) or XML (extensible markuplanguage), (ii) assembly code, (iii) object code generated from sourcecode by a compiler, (iv) source code for execution by an interpreter,(v) source code for compilation and execution by a just-in-timecompiler, etc. As examples only, source code may be written using syntaxfrom languages including C, C++, C #, Objective-C, Haskell, Go, SQL, R,Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5,Ada, ASP (active server pages), PHP, Scala, Eiffel, Smalltalk, Erlang,Ruby, Flash®, Visual Basic®, Lua, and Python®.

Further, at least one embodiment of the invention relates to thenon-transitory computer-readable storage medium including electronicallyreadable control information (processor executable instructions) storedthereon, configured in such that when the storage medium is used in acontroller of a device, at least one embodiment of the method may becarried out.

The computer readable medium or storage medium may be a built-in mediuminstalled inside a computer device main body or a removable mediumarranged so that it can be separated from the computer device main body.The term computer-readable medium, as used herein, does not encompasstransitory electrical or electromagnetic signals propagating through amedium (such as on a carrier wave); the term computer-readable medium istherefore considered tangible and non-transitory. Non-limiting examplesof the non-transitory computer-readable medium include, but are notlimited to, rewriteable non-volatile memory devices (including, forexample flash memory devices, erasable programmable read-only memorydevices, or a mask read-only memory devices); volatile memory devices(including, for example static random access memory devices or a dynamicrandom access memory devices); magnetic storage media (including, forexample an analog or digital magnetic tape or a hard disk drive); andoptical storage media (including, for example a CD, a DVD, or a Blu-rayDisc). Examples of the media with a built-in rewriteable non-volatilememory, include but are not limited to memory cards; and media with abuilt-in ROM, including but not limited to ROM cassettes; etc.Furthermore, various information regarding stored images, for example,property information, may be stored in any other form, or it may beprovided in other ways.

The term code, as used above, may include software, firmware, and/ormicrocode, and may refer to programs, routines, functions, classes, datastructures, and/or objects. Shared processor hardware encompasses asingle microprocessor that executes some or all code from multiplemodules. Group processor hardware encompasses a microprocessor that, incombination with additional microprocessors, executes some or all codefrom one or more modules. References to multiple microprocessorsencompass multiple microprocessors on discrete dies, multiplemicroprocessors on a single die, multiple cores of a singlemicroprocessor, multiple threads of a single microprocessor, or acombination of the above.

Shared memory hardware encompasses a single memory device that storessome or all code from multiple modules. Group memory hardwareencompasses a memory device that, in combination with other memorydevices, stores some or all code from one or more modules.

The term memory hardware is a subset of the term computer-readablemedium. The term computer-readable medium, as used herein, does notencompass transitory electrical or electromagnetic signals propagatingthrough a medium (such as on a carrier wave); the term computer-readablemedium is therefore considered tangible and non-transitory. Non-limitingexamples of the non-transitory computer-readable medium include, but arenot limited to, rewriteable non-volatile memory devices (including, forexample flash memory devices, erasable programmable read-only memorydevices, or a mask read-only memory devices); volatile memory devices(including, for example static random access memory devices or a dynamicrandom access memory devices); magnetic storage media (including, forexample an analog or digital magnetic tape or a hard disk drive); andoptical storage media (including, for example a CD, a DVD, or a Blu-rayDisc). Examples of the media with a built-in rewriteable non-volatilememory, include but are not limited to memory cards; and media with abuilt-in ROM, including but not limited to ROM cassettes; etc.Furthermore, various information regarding stored images, for example,property information, may be stored in any other form, or it may beprovided in other ways.

The apparatuses and methods described in this application may bepartially or fully implemented by a special purpose computer created byconfiguring a general purpose computer to execute one or more particularfunctions embodied in computer programs. The functional blocks andflowchart elements described above serve as software specifications,which can be translated into the computer programs by the routine workof a skilled technician or programmer.

Although described with reference to specific examples and drawings,modifications, additions and substitutions of example embodiments may bevariously made according to the description by those of ordinary skillin the art. For example, the described techniques may be performed in anorder different with that of the methods described, and/or componentssuch as the described system, architecture, devices, circuit, and thelike, may be connected or combined to be different from theabove-described methods, or results may be appropriately achieved byother components or equivalents.

The radiation detector of at least one embodiment comprises anintermediate layer, which is arranged between a detection layer with anumber of detection elements and a number of readout units. In this casethe intermediate layer has a plurality of electrically-conductiveconnections between the detection elements and the readout units.

The radiation detector, in at least one embodiment, is a layerarrangement of layers preferably arranged essentially in parallel. Inthis case “essentially” means that the layers can also be slightlycurved. By contrast with the prior art, in accordance with at least oneembodiment of the invention, an intermediate layer is thus arrangedbetween the detection layer and the readout units. The readout units areexplicitly not connected directly to the detection layer, but areconnected indirectly via the intermediate layer.

The intermediate layer, in at least one embodiment, has two opposingplanar sides, wherein the detection layer is arranged adjacent to oneplanar side, which will be referred to below as the upper side. Thereadout units are arranged adjacent to the opposing planar side, whichwill also be referred to below as the lower side. The intermediate layercan in this case basically be designed as a continuous layer over theentire detector, which has an especially advantageous effect of thestability or rigidity. It can however also be formed from a number ofintermediate layer elements arranged within the intermediate layer,which makes manufacturing easier.

The detection layer, in at least one embodiment, is generally embodiedso that, by means of the detection elements, it converts the incidentradiation into a usually analog electrical signal. Depending on thepurpose for which it is used, the radiation detector can serve tomeasure electromagnetic radiation of different wavelengths and/or tomeasure particle radiation. To do this the detection layer comprisesdetection elements corresponding to the relevant detector type.

For example in indirect-converting X-ray detectors (also calledintegrating detectors), initially, following on from the upper side ofthe intermediate layer, a plurality of photodiodes is arranged asdetection elements in a first sublayer of the detection layer, which isarranged in parallel to the intermediate layer. This is followed in itsturn by a second sublayer of the detection layer in parallel theretowith a scintillator as a further detection element. This convertsincident X-ray radiation into light in the visible wavelength. Thescintillator of the second sublayer can extend continuously over wideareas of the detector, however it is preferably embodied in a modulardesign as a number of scintillator elements. The visible light createdby the scintillator will subsequently be transmitted to the respectivespatially assigned photodiode, which for its part converts it into anelectrical signal.

With direct-converting detectors (also called photon-counting detectors)the incident radiation will be converted directly into an electricalsignal for example, preferably in a semiconductor material. Detectors ofthis type therefore preferably comprise as their detection elementssensor elements made of Si (silicon), GaAs (gallium arsenide), HgI2(mercury iodide) and/or a-Se (amorphous selenium), especially preferablymade of CdTe (cadmium telluride) and/or CdZnTe (cadmium zinc telluride).

In both types, the detector comprises, in at least one embodiment, aplurality of pixels in each case, i.e. the smallest surface areas withinthe detection layer that can be read out independently. In order for itto be read out, each pixel is connected to a readout unit. In this casea number of pixels are preferably connected to one readout unit. Theseconnections too are realized by way of the intermediate layer. Theintermediate layer is conductively connected in this case preferably viaa plurality of solder or adhesive connections on one side to the pixelsof the detection layer. On the other side it is connected by way of justsuch connections to the readout units. The surface of the detectionlayer preferably corresponds to the surface of the intermediate layer,so that all pixels of the detection layer are each connected to areadout unit via the intermediate layer with the same overall surfaceand possibly of modular design.

The readout units generally serve to digitize electronic signals fromthe detection elements. They are preferably implemented as an ASIC(application specific integrated circuit). In such cases they preferablyalso comprise additional evaluation units. In the units for example, indirect-converting detectors, the electronic signals detected at therespective pixels are amplified as pulses, shaped and counted orsuppressed, depending on pulse height and threshold value.

With different lengths of the lines—i.e. the connections from pixel toreadout unit—different input capacitances will be created for thereadout unit, as has already been explained above. However the inputcapacitances are preferably adapted to the readout units following themor to the evaluation units by so-called adaptation structures, so thatit is possible work even with longer lines and even lines of differentlengths. An adaptation structure is basically to be understood here asany possible adaptation of the capacitance. I.e. the adaptationstructures change the capacitance for example on the basis of theirgeometrical layout such as form, diameter and/or length and/or a changedpermittivity. In such cases however a balance is to be struck betweenthe possibly greater line lengths and an increased electronic noise,which results in an inferior energy resolution. Consequently acompromise should be found between the energy resolution and theproduction costs in the design of the detector.

The intermediate layer (interposer), in at least one embodiment, thusoverall represents a diverter layer or rewiring layer and also enhancesthe stability of the detector structure. It decouples the surfaces ofthe individual detection elements, i.e. also the overall surface of thedetection layer, from the surfaces of the readout units. I.e. thereadout units can preferably be designed smaller and no longer have totake up the entire detector surface. The intermediate layer thus mayrepresent a paradigm shift in the development of radiation detectors;since in the current prior art the readout unit is arranged as directlyas possible on the detection layer. By means of the reduction of thesurface taken up by the readout units a price reduction in themanufacturing of an inventive radiation detector can thus also beachieved.

In at least one embodiment, the radiation detector has a heatingapparatus. This comprises at least one heating element, which isarranged between a detection layer with a number of detection elementsand a number of readout units. The at least one heating element is thusadjacent both to the readout units and also to the detection layer. Insuch cases it can be embodied so that it can emit an introduced heatingpower as homogeneously as possible over the entire surface of thedetector. Especially preferably however a number of heating elements aredistributed evenly and in particular areas over the surface of thedetector so that individual areas of the radiation detector can besupplied with different heating power. This enables a temperaturestabilization appropriate for the material of the detection elements orfor the sensor material also to be achieved in different areas of thesensor material.

Furthermore the heating element can also be embodied so that, dependingon requirements, it can introduce both a positive heating power and alsoa negative heating power into the detector. To this end for example itcan act as a heating line, which is coupled to a Peltier element, whichcan both heat and also cool. In a simple manner the heating element canhowever also be embodied as a heating wire for example, of which theheating power is regulated by a current flowing through it.

The radiation detector illustrated here with the heating apparatus canbe advantageously used as a self-contained idea independently of thepreviously described radiation detector, i.e. also without theintermediate layer with the conductive connections. Then the heatingapparatus could be arranged for example in free spaces between thedirect contacts between detection elements and readout units. Especiallysynergetic effects are produced however if the heating element of theheating apparatus is integrated into the intermediate layer of thepreviously described radiation detector. This is because it is preciselythe intermediate layer that would otherwise make a heat transfer moredifficult from heating elements usually arranged below the ASIC. At thesame time the intermediate layer advantageously provides the space toarrange the heating element inventively in the detector.

The medical imaging system (e.g. CT), in at least one embodiment,comprises at least one embodiment of the radiation detector, preferablya direct-converting X-ray detector. The comparatively large surface ofthe detector in computed tomography results here for an inventiveradiation detector in an especially large potential for savings in themanufacturing costs. In addition the effect of the heating apparatuscomes into play especially effectively at the high radiation fluxdensities in CT devices and the high power losses associated therewith.

In particular with direct-converting X-ray detectors the resistance ofthe sensor material changes with the flux of X-ray radiation radiatedin. This also leads at the same time to a change of the measured signaldependent on the X-ray flux, i.e. the counting rate and energyresolution. This signal change can be compensated for however, in thatdepending on the X-ray radiation variation, the heating power is alsovaried. Therefore, in accordance with at least one embodiment of theinvention, a heating apparatus is used for heating a radiation detector.It is arranged in this case between a detection layer with a number ofdetection elements and a number of readout units. In addition a controldevice controls the heating apparatus and regulates a heating lineintroduced into the radiation detector.

Further especially advantageous embodiments and developments of theinvention emerge from the dependent claims and also from the descriptiongiven below, wherein the independent claims of one claim category canalso be developed analogously to the dependent claims of another claimcategory and their description and in particular also individualfeatures of different example embodiments or variants can be combined toform new example embodiments or variants.

In at least one embodiment of the inventive radiation detector, anoverall surface of the detection elements is preferably large comparedto an overall surface of the readout units. I.e. the sum of theindividual surfaces of the detection elements is large compared to thesum of the individual surfaces of the readout units. Especiallypreferably the overall surface of the detection elements is twice aslarge, quite especially preferably four times as large as the overallsurface of the readout units. This is because the more of the surface ofthe readout units that can be saved compared to the prior art, thegreater is also the cost reduction.

Basically at least one embodiment of the inventive radiation detectorcan be used for detection of any given ionizing radiation, such as forexample Alpha or Beta particles. Preferably however it is embodied fordetection of X-ray radiation. X-ray radiation involves electromagneticradiation with wavelength ranging from 1 to 250 picometers.

Preferably the electrically-conductive connections in an inventiveradiation detector are embodied as vias and rewiring structures. Throughthese the individual pixels of the detection layer are connected tocorresponding interfaces of the readout units. The intermediate layer ispenetrated by the vias at right angles to the planar sides. The rewiringstructures in this case refer to structures of conductor tracks thatextend in a plane parallel to the planar sides of the intermediatelayer. Thus a spatial re-arrangement of the conductive connectionswithin this plane is achieved by means of the rewiring structures.

The intermediate layer in at least one embodiment of the inventiveradiation detector, on a side facing towards the readout units, has arewiring structure. I.e. the rewiring structure is preferably arrangedon the lower side of the intermediate layer. Especially preferably theintermediate layer has the rewiring structure exclusively on the lowerside.

For various reasons high demands may be placed on the substrate of whichthe intermediate layer consists. On the one hand for example in a CTdevice as carrier unit it should withstand the centrifugal forces (50g-80 g depending on speed of rotation) in the detector and may notdeform under such forces. The surface integrity, ripple, dimensions etc.may lie in a very narrow tolerance range, so that the alignment of thepixel matrix to the focus as a subunit in the detector is possible andthere are no resulting image artifacts. This may be guaranteed by themanufacturing process itself. The further components (detection units,ASICs etc.) of the detector may be able to be placed highly-precisely.Here too there may be mandatory specifications on the manufacturingprocess side, e.g. on the ripple inter alia. Furthermore the reliabilityof the entire assembly should be guaranteed over 10 years. The assemblymay be realized by multiple and complex soldering and gluing processes.The deviations of the different coefficients of thermal expansion of theindividual subcomponents in such cases should be kept as low aspossible, so that with thermal changes the induced stress remains lowand the reliability and lifetime as high as possible.

The counting technology of the direct-converting detectors especiallyimplies particular requirements on the rigidity of the substrate. WhenCdTe is used as the sensor material it is shown for example, thatinduced mechanical stresses influence the crystal structure and as aresult the signal stability is no longer guaranteed. There then namelyarise so-called high drift regions or drift spots, so that the detectormay no longer be suitable for CT imaging. For the substrate this meansthat it may no longer deform after the attachment of the CdTe sensor andalso may not exert any or only exert slight mechanical stresses on thesensor material in the event of thermal fluctuations.

Therefore, in at least one embodiment of an inventive radiationdetector, the intermediate layer preferably has a substrate made of aglass fiber composite material, phenolic paper, ceramics and/orespecially preferably glass. A glass fiber composite material in thiscase is to be understood as a combination material made of epoxy resinand glass fiber material. Ceramics refers to a material made of aplurality of anorganic non-metallic materials by molding and burning.Phenolic paper is fiber composite material made of paper and a syntheticresin, preferably phenoplast, which especially preferably isfire-retardant in accordance with class FR-4. For all of the thematerials the aforementioned requirements imposed on the substrate canbe fulfilled in combination with at least one embodiment of theinventive layout, as will be described below in greater detail.

Glass is especially preferred as a substrate, because with this materialthe vias can be created via an etching process and do not have to bedrilled mechanically. This leads to a more favorable aspect ratio, i.e.a better ratio of height to width of the vias produced. In other words,with glass, more vias per surface can be created, so that more freespace is left between the vias (with the same density) for the rewiringstructures and also if necessary for the heating elements.

The heating element is preferably embodied for at least one embodimentof an inventive radiation detector as a serpentine electrical conductor.It is thus arranged in the shape of a rectangle function alternating andpreferably in turn on the upper side and the lower side of theintermediate layer. The heating element is thus quasi introduced as ahook-shaped heater into the intermediate layer by means of recessesetched on both sides for example. Especially preferably intermediatespaces are used for this, which are present between the conductiveconnections that connect the detection elements with the readout units.With the aid of the arrangement of the heating element in this way onboth sides the introduced heating power can advantageously be emittedevenly to both adjacent sides, i.e. both to the detection elements andalso to the readout units.

In at least one embodiment of an inventive radiation detector theheating apparatus preferably comprises a control device that regulatesthe heating power that is introduced into the radiation detector. Theheating power can be adapted for example via a simple temperaturemeasurement and a corresponding regulation circuit and/or as a functionof a radiation power detected by the detector.

At least one embodiment of an inventive radiation detector preferablyalso comprises a number of conductive support structures, which serve onthe one hand to forward the data from the readout units or evaluationunits, which thus for example transmit the data in conjunction withother components to a reconstruction unit. On the other hand the supportstructures can also function however as a carrier element between theintermediate layer and for example a carrier layer lying below it. Tothis end the conductive support structures are arranged in a layer withthe readout units or evaluation units. A conductive support structureespecially preferably comprises a number of elements for forwarding thedata of the readout unit, which can basically be embodied in a differentmanner, e.g. as a so-called ball stack structure. This refers to astacked arrangement of solder balls and circuit boards with rewiringstructures.

Such a conductive support structure makes it possible for the rewiringstructures of the inventive intermediate layer to be kept simple, i.e.especially single-layer, by comparison with known multi-layer rewiringstructures. By this means the stability of the intermediate layer isadvantageously increased and the manufacturing process simplified.

FIG. 1 shows an example of a schematic sectional diagram of adirect-converting radiation detector 1* according to the prior art. Theradiation detector 1* is composed of a number of parallel layers here.

A first layer is formed by two semiconductor sensors 4 arranged next toone another, for example CdTe sensors. In a second layer lying belowthis layer ASICs 5 are arranged next to one another. The ASICs 5 of thesecond layer are connected directly via solder connections 10 to thesemiconductor sensors 4. In this case they extend over an overallsurface that is exactly the same size as the overall surface of thesemiconductor sensor 4. Arranged below the second layer as a third layeris a ceramic carrier layer 15*. This is usually embodied as an LTCClayer 15* (Low Temperature Co-fired Ceramics). I.e. it is a multi-layercircuit based on sintered ceramic carriers. The ASICs 5 are in directconductive contact with the carrier layer 15* here via solderconnections 14, wherein there is rewiring within the circuit of the LTCClayer 15*. Via the carrier layer 15* the radiation detector 1* isconnected by means of a connector 16, which acts as input or outputinterface of the radiation detector 1*, for example with furtherevaluation units (not shown here) such as for example a reconstructiondevice of a CT device.

Incident radiation to be detected during operation is thus convertedhere by the semiconductor sensors 4 into an analog electrical signal,then read out directly by the ASICs 5, evaluated and digitized.Subsequently it is forwarded via the carrier layer 15* and the connector16.

FIG. 2 shows a rough schematic diagram of an example embodiment of aninventive radiation detector 1 in the form of a direct-converting,photon-counting X-ray detector. By contrast with the prior art explainedwith reference to FIG. 1, the inventive radiation detector 1 comprisesan intermediate layer 2. This is arranged below a detection layer 3 withtwo semiconductor sensors 4 as detection elements 4. The semiconductorsensors 4 comprise a plurality of pixels, which are connected via solderconnections 10 to the intermediate layer 2.

The intermediate layer 2 has two planar sides, of which one, namely theupper side, points towards the detection layer 3. Vias 6 extend at rightangles to the planar sides of the intermediate layer 2 in theintermediate layer 2, which are each connected via one of the solderconnections 10 to a pixel of a semiconductor sensor 4. The vias 6 arepreferably inserted by means of an etching process into a substrate 11of the intermediate layer. Glass is preferably used as the substrate 11.The intermediate layer 2, on its planar side, namely a lower side, whichlies opposite the upper side, has rewiring structures 7. The rewiringstructures 7 in this case comprise conductor tracks, which are eachconnected by means of a via to a pixel of the semiconductor sensor 4.The radiation detector 1 further comprises two ASICs 5, which functionas the readout unit 5. Each of the conductor tracks is connected via acontact to an input of an ASIC 5. Thus, by means of the rewiringstructures 7, a spatial rearrangement is achieved in a plane in parallelto the planar sides of the intermediate layer 2. This enables the pixelsthat are distributed evenly over the relatively large surface of thesemiconductor sensor 4 to be connected to the ASIC 5, which has acomparatively small surface.

The ASICs 5 are arranged in this case in a third layer below theintermediate layer 2. In this third layer so-called ball stackstructures are arranged as conductive support structures 12 next to theASICs 5. The ball stack structures 12 are a layered arrangement ofparallel printed circuit boards 13 and solder balls 14 arranged betweenthe boards, which connect the circuit boards 13 to one another. Thecircuit boards are at the same time arranged in parallel to the layers2, 3 of the radiation detector 1. They can consist of prepreg forexample and have rewiring structures embodied by means of usual methods.A significant portion of the rewiring necessary in the radiationdetector 1 is done in these ball stack structures 12.

The ASICs 5 also have outputs, which are connected via the intermediatelayer 2 to the ball stack structures 12. A carrier layer 15 is arrangedbelow the third layer. The carrier layer 15 has conductor tracks, whichare connected conductively via solder balls 14 to the ball stackstructures. Compared to the prior art, the carrier layer 15 can bedesigned more simply and thereby at lower cost, since the rewiring, asalready described, is largely done in the ball stack structures 12. Theconductor tracks of the carrier layer 15 are routed jointly to oneconnector 16. Via this the inventive radiation detector can also beconnected to further evaluation units (not shown here) such as forexample an evaluation computer or a reconstruction device of a CTdevice.

The signal flow in the inventive radiation detector is as follows:Incident X-ray radiation is converted in the semiconductor sensors 4into an analog electrical signal. The analog signal is forwarded via thesolder connections 10 to the vias 6 in the intermediate layer 2. On thelower side of the intermediate layer 2 it is diverted spatially in therewiring structure 7, i.e. the signal of a respective pixel is routed bymeans of a conductor track to the input of the ASIC 5 associated withit. In the ASIC 5 the signal is read out and evaluated, i.e. amplifiedas a pulse, shaped and counted or suppressed, depending on pulse heightand threshold value. In the ASIC 5 the signal is also digitized. Fromthe output of the ASIC 5 the digital signal in its turn is conveyed viathe rewiring structure 7 of the intermediate layer 2 to a ball stackstructure 12. In the ball stack structure the digital signals from theoutputs of the ASICs 5 are rewired again as far as necessary, i.e.spatially diverted and finally conveyed via the carrier layer 15 to theconnector 16 as output interface of the radiation detector.

Conversely the connector 16 can also act as the input interface forexample for control signals of the radiation detector 1. These then takethe analogous reverse path through the carrier layer 15, ball stackstructure 12 and rewiring structure 7 to the control input of the ASIC.They can be used for example to define energy thresholds in the ASIC 5for the X-ray quanta to be counted or to control the regulation of aheating apparatus (cf. FIG. 4).

FIG. 3 shows a similar radiation detector 1′ to that shown in FIG. 2 byway of example and as a rough schematic diagram, but here however in theform of an integrating X-ray detector 1′. By contrast with FIG. 2, notjust two semiconductor sensors 4, but also an arrangement with two lowerlayers are located here in the detection layer 3. A scintillator 4″ isarranged as a detection element in the top lower layer, pointingoutwards, which converts incident X-ray radiation into visible light.Four photodiodes 4′ are arranged next to one another in the bottom lowerlayer arranged below this layer, to which the visible light from thescintillator 4″ is transmitted. The photodiodes 4′ extend together overthe surface of the scintillator 4″ and convert the visible light into anelectrical signal assigned to the pixel, which is forwarded via a solderconnection 10 to the intermediate layer 2. From the solder connections10 onwards, the detector structure described here is the same as thatdescribed for FIG. 2, so that the reader is similarly referred to thispoint.

FIG. 4 likewise shows by way of example and as a rough schematic diagraman inventive radiation detector 1″ similar to that shown in FIG. 2, buthere with a heating apparatus 8. The heating apparatus 8 comprises aheating element 9. This is embodied as a heating wire 9, which isarranged between the vias 6 and the rewiring structures 7 in theintermediate layer 2. The heating wire 9 has the form of a rectanglefunction (serpentine) and extends alternately in sections in parallel toand on the upper side or the lower side of the intermediate layer 2,wherein the sections are each connected to one another with additionalvias at right angles to the upper side or lower side. The radiationdetector 1″ shown here—jointly for the two semiconductor sensors 4—hasonly one ASIC 5, which is arranged centrally and is connected in asimilar way by means of the vias 6 and the rewiring structures 7 of theintermediate layer 2 to the individual pixels of both semiconductorsensors 4. A control device of the heating apparatus 8, which regulatesthe heating power, which is introduced into the radiation detector 1″ isadditionally implemented here in the ASIC 5.

FIG. 5 shows a graph to explain the regulation of the heating apparatus.Powers occurring in the radiation detector 1″ from FIG. 4 are plotted onthe vertical axis P in a timing curve against the horizontal axis t. Apower loss X created by the X-ray radiation is shown as a dashed line,while an introduced heating power H of the heating apparatus 8 is shownas a dark line. The two functions have a similar opposing shape, so thata sum of the power losses L occurring in the detector remains constant.For this the heating power H introduced by the heating apparatus 8 willbe regulated as a function of the incident X-ray intensity measured inthe radiation detector 1″ by a control device implemented in the ASIC 5.The overall power loss L kept constant can already to taken into accountin the design of the detector, so that artifacts can be avoided duringimaging.

FIG. 6 shows, by way of example and as a rough schematic diagram, aninventive medical imaging system 20, here as a concrete example of acomputed tomography device 20. The computed tomography device 20comprises a patient table 25 for supporting a patient 24 as examinationobject. The patient table 25 is displaceable along a system axis 26 intothe measuring field, via which the patient 24 can be positioned in themeasurement field. The computed tomography device 20 further comprises agantry 22 with a source radiation detector arrangement 23, 1, 1′, 1″arranged rotatably about the system axis 26. The source radiationdetector arrangement 23, 1, 1′, 1″ has an X-ray radiation source 23 anda radiation detector 1, 1′, 1″, which are aligned opposite one anotherso that, in operation, outgoing X-ray radiation from the focus of theX-ray radiation source 23 strikes the radiation detector 1, 1′, 1″. Theradiation detector 1, 1′, 1″ is structured for spatially-resolveddetection of the X-ray radiation into individual pixels 21, which arearranged into a number of radiation detector rows. For each projectionthe radiation detector 1, 1′, 1″ creates a set of projection data. Thisprojection data is subsequently further processed and computed to form aresulting image.

It is known that such a computed tomography device 20 is used for 3Dimage reconstruction. To record an image of a region of interest, duringrotation of the source radiation detector arrangement 23, 1, 1′, 1″,projection data is detected from a plurality of different projectiondirections. In the case of spiral scanning, during a rotation of thesource radiation detector arrangement 23, 1, 1′, 1″ for example, thereis a continuous displacement of the patient table 25 in the direction ofthe system axis 26. With this type of scanning, the X-ray radiationsource 23 and the radiation detector 1, 1′, 1″ thus move on a helicalpath about the patient 24. The exact structure and the actual way inwhich such a CT operates are known to the person skilled in the art andwill therefore not be explained in detail here.

In conclusion it is pointed out once again that the devices and methodsdescribed here in detail merely involve example embodiments, which canbe modified by the person skilled in the art in a wide diversity ofways, without departing from the area of the invention. Furthermore theuse of the indefinite article “a” or “an” does not exclude the featuresconcerned also being present more than once. Likewise the terms“facility”, “unit” and “system” do not exclude the components concernedconsisting of a number of interacting sub-components, which if necessarycan also be spatially distributed. Thus the control device of theheating apparatus for example can be integrated in the readout unit orevaluation unit and/or be implemented in a central control device forthe medical imaging system.

The patent claims of the application are formulation proposals withoutprejudice for obtaining more extensive patent protection. The applicantreserves the right to claim even further combinations of featurespreviously disclosed only in the description and/or drawings.

References back that are used in dependent claims indicate the furtherembodiment of the subject matter of the main claim by way of thefeatures of the respective dependent claim; they should not beunderstood as dispensing with obtaining independent protection of thesubject matter for the combinations of features in the referred-backdependent claims. Furthermore, with regard to interpreting the claims,where a feature is concretized in more specific detail in a subordinateclaim, it should be assumed that such a restriction is not present inthe respective preceding claims.

Since the subject matter of the dependent claims in relation to theprior art on the priority date may form separate and independentinventions, the applicant reserves the right to make them the subjectmatter of independent claims or divisional declarations. They mayfurthermore also contain independent inventions which have aconfiguration that is independent of the subject matters of thepreceding dependent claims.

None of the elements recited in the claims are intended to be ameans-plus-function element within the meaning of 35 U.S.C. § 112(f)unless an element is expressly recited using the phrase “means for” or,in the case of a method claim, using the phrases “operation for” or“step for.”

Example embodiments being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the present invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

What is claimed is:
 1. A radiation detector comprising: a detectionlayer including a plurality of detection elements; at least one readoutunit; an intermediate layer, arranged between the detection layer andthe at least one readout unit, the intermediate layer including aplurality of electrically-conductive connections each respectivelyarranged between respective ones of the plurality of detection elementsand the at least one readout unit; and a heating apparatus, including atleast one heating element, arranged between the detection layer and theat least one readout unit, wherein the at least one heating element isembodied as a serpentine electrical conductor that extends along twoplanar side surfaces of the intermediate layer.
 2. The radiationdetector of claim 1, wherein an overall surface of the plurality ofdetection elements is relatively large compared to an overall surface ofthe at least one readout unit.
 3. The radiation detector of claim 2,wherein the radiation detector is embodied for detection of X-rayradiation.
 4. The radiation detector of claim 1, wherein the radiationdetector is embodied for detection of X-ray radiation.
 5. The radiationdetector of claim 1, wherein the plurality of electrically-conductiveconnections are embodied as vias and rewiring structures.
 6. Theradiation detector of claim 5, wherein the intermediate layer includesthe rewiring structures on a side facing towards the at least onereadout unit.
 7. The radiation detector of claim 1, wherein theintermediate layer comprises a substrate made from at least one of aglass fiber composite material, phenolic paper, ceramics and glass. 8.The radiation detector of claim 1, further comprising a supportstructure, including a plurality of elements configured to forward datafrom the at least one readout unit.
 9. The radiation detector of claim8, wherein the support structure is a conductive support.
 10. Theradiation detector of claim 1, wherein the heating apparatus comprises acontrol device, configured to regulate heating power introduced into theradiation detector.
 11. The radiation detector of claim 1, wherein theheating apparatus includes a plurality of heating elements distributedevenly in areas over a surface of the detector layer.
 12. The radiationdetector of claim 1, wherein the at least one heating element isconfigured to introduce both a positive heating power and a negativeheating power into the detector layer.
 13. The radiation detector ofclaim 1, wherein the at least one heating element is arranged in theshape of a rectangle function alternating in turn on an upper surfaceand a lower surface of the intermediate layer.
 14. The radiationdetector of claim 1, wherein the at least one heating element isarranged in a recess in the intermediate layer.
 15. The radiationdetector of claim 1, wherein the at least one heating element isarranged between the plurality of electrically-conductive connections.16. A medical imaging system comprising the radiation detector ofclaim
 1. 17. The radiation detector of claim 1, wherein the heatingelement passes from one of the two planar side surfaces of theintermediate layer to the other of the two planar side surfaces of theintermediate layer and passes between vias that traverse through theintermediate layer.